Over recent decades, developments in data communications technologies have continued to provide enhanced multimedia services (e.g., voice, data, video, etc.) to end-users. Such communications technologies encompass various delivery platforms, including terrestrial wire-line, fiber and wireless communications and networking technologies, and satellite communications and networking technologies. Further, in recent years, the proliferation of mobile communications has spurred an exponential growth in the provision of such enhanced multimedia services over mobile communications networks (both terrestrial and satellite based). As part of the continued evolution of such communications platforms and supporting technologies, the Digital Video Broadcasting (DVB) organization was formed (as an industry-led, global consortium of broadcasters, manufacturers, network operators, software developers, regulatory bodies and others) to advance the design of open interoperable standards for the global delivery of digital media and broadcast services.
As part of the standardization process for digital media and broadcast services, the DVB organization managed the adoption and publication of the DVB-S2 standard via recognized standards setting organizations (e.g., ETSI and TIA). DVB-S2 is a digital satellite transmission system standard covering framing structure, channel coding and modulation systems, designed for broadcast services (for standard and high definition television), interactive services (e.g., Internet access for consumer applications), and other broadband satellite applications. DVB-S2 represents a flexible standard, covering a variety of data and multimedia services delivered over satellite communications systems. The DVB-S2 standard covers various technological features, such as a flexible input stream adapter (suitable for operation with single and multiple input streams of various formats), a robust forward error correction coding (FEC) system based on low-density parity check (LDPC) codes concatenated with BCH codes, a wide range of code rates (from 1/4 up to 9/10), four signal constellations (ranging in spectrum efficiency from 2 bit/s/Hz to 5 bit/s/Hz), and adaptive coding and modulation (ACM) functionality (optimizing channel coding and modulation on a frame-by-frame basis).
Since its inception, the DVB-S2 standard has been adopted globally as a predominant standard for broadcast, interactive and other broadband services over satellite communications networks. Currently, there are applications, particularly in the field of mobile communications, that require lower signal-to-noise ratios (Es/N0), down to approximately −9 dB to −10 dB. The current DVB-S2 frame format, however, supports operation down to Es/N0 ratios of only about −3 dB, and thus the existing DVB-S2 frame format cannot support the operational requirements of such current mobile applications. Further, more recently an extension has been added to the DVB-S2 standard (“DVB-S2 Wideband”). In the wideband extension, the modulation and coding field was increased in size, and a different code was employed, as compared with the original DVB-S2. This wideband extension of the DVB-S2 standard, however, also fails to support the lower signal-to-noise ratio requirements of current mobile applications.
What is needed, therefore, are systems and methods to address the challenges arising from communications system requirements associated with the support of current and future communications services and applications (particularly in the field of mobile communications) over relatively low signal-to-noise ratio (Es/N0) links with corresponding low signal-to-noise ratio communications terminals.